The proposal responds to a Request for Applications (RFA) from NIH. It combines naturalistic and experimental methods to study the informed consent process in psychiatric and medical treatment research. The project is based at the Clinical Research Center for the Study of Adult Schizophrenia, an NIMH-funded research organization now entering its 20th year. Participants for this study will be drawn from volunteers with schizophrenia and bipolar disorder, two serious mental illnesses that have symptomatic and cognitive features in common, and a comparison group of coronary transplant patients without mental illness. All subjects will be in the process of being recruited for one of several large, ongoing, randomized, clinical trials of medications for their serious, chronic illness. The use of people making important health care decisions is a departure of this project from most previous research on this topic, which has involved people in hypothetical decision-making situations. The research includes a plan for careful assessment of basic cognitive capacities, disturbances of thinking and mood, and social influence factors. A randomized experimental design will evaluate the efficacy of a novel method of disclosure of mandated informed consent content. Major dependent variables include objective and open-ended measures of acquisition and comprehension of mandated informed consent, and measures describing the coherence of the decision making process. Follow-up at three months will determine stability of these outcomes over times as a function of the treatment experience itself, and of changes in health and symptom status.